In the related art, there has been a seating detection device that determines a state in which an occupant is seated on a seating surface based on an ON/OFF state of a membrane switch disposed inside a seat skin that constitutes a seat surface (the seating surface) of a seat cushion.
For example, a seating detection device disclosed in JP 2005-153556A (Reference 1) is provided with a membrane switch having a plurality of pressure sensitive switch units (cells). Specifically, the membrane switch is configured in a manner in which the membrane switch is disposed inside the seat skin such that respective pressure sensitive switch units are disposed to be spaced apart from one another along the seating surface. In addition, the membrane switch is configured to be in an ON state when at least two pressure sensitive switch units among the respective pressure sensitive switch units are simultaneously in an electric conduction state. Therefore, the membrane switch is configured to avoid the occurrence of incorrect detection (for example, determining baggage or the like placed on the seating surface as an occupant).
In addition, a pressure sensitive sensor such as the membrane switch is typically disposed in a central portion of the seating surface, which corresponds to a hip point of the occupant, in order to ensure that a seating state of an occupant is determined. In contrast, in many cases, a child seat has a larger lower surface than an occupant seating portion. Further, in most instances, side support portions, each having a bulging shape, are provided at both end portions in a width direction of the seat cushion. That is, in the case of most of the seating surfaces, the height of the central portion of a seating surface where the pressure sensitive sensor is provided is lower than those of peripheral portions. Further, with the aforementioned configuration, most of seating detection devices are configured in a manner in which the pressure sensitive switch unit is not turned into the ON state even in a case in which an occupant (child) is seated on the child seat mounted on the seat.
In a case in which a foreign object (e.g., a toy or a lighter) is inserted into a gap between a seating surface and a child seat, the seating surface is likely to be pressed by the foreign object. Therefore, because a pressure sensitive switch unit is turned into the ON state when an occupant is seated on the child seat, there is a likelihood that an error will occur in respect to seating detection and determination.
Thus, a need exists for a seating detection method and a seating detection device which are not susceptible to the drawback mentioned above.